PROFIsafe
PROFIsafe (PROFIBUS safety or PROFINET safety) is a safety communication technology for distributed automation. Its specification for PROFIBUS DP and PROFIBUS PA was published first in 1999. Extensions for the Ethernet based PROFINET IO followed in 2005.
The IEC 61508 standard specified how microcontrollers and software can be used in safety automation. This triggered the development of PROFIsafe, which was to integrate safety into the existing standard PROFIBUS fieldbus technologies. PROFIsafe is designed as a separate layer on top of the fieldbus application layer to reduce the probability of data transmission errors. PROFIsafe messages use standard fieldbus cables and messages. PROFIsafe does not depend on error detection mechanisms of underlying transmission channels, and thus supports securing of whole communication paths, including backplanes inside controllers or remote I/O. PROFIsafe coined the term "Black Channel" for this concept, which was adopted by other safety fieldbusses. PROFIsafe can be used in safety applications up to Safety Integrity Level 3 (SIL) according to IEC 61508, Performance Level "e" (PL) according to ISO 13849, or Category 4 according to EN 954-1.
PROFIsafe uses error and failure detection mechanisms such as:
- Consecutive numbering
- Timeout monitoring
- Source/destination authentication
- Cyclic redundancy checking (CRC)
PROFIsafe was standardized in IEC 61784-3-3 and Chinese standard (GB/Z 20830-2007).
PROFIsafe runs its own web portal with more details on the technology and hints for device developers, integrators and end users. The PROFIsafe standard is maintained, updated and marketed by PROFIBUS International, a non-profit organisation administered from Karlsruhe in Germany. PROFIBUS International is also responsible for the development of PROFIBUS and PROFINET, an Ethernet based fieldnetwork.